Configuration Guide

Hot Failover Operation Options

Hot Failover (HF) allows your applications to build in sender redundancy. See Hot Failover in the Ultra Messaging Concepts Guide for a discussion of using Hot Failover within a single receiver context or across multiple receiver contexts.

# Reference <-

## delivery_control_loss_check_interval (hfx) <-

  The interval between periodic forced loss checks.

  This option defaults to 0, indicating that loss checks should only be made when a new message arrives.

  Scope: | hfx
  Type: | lbm_ulong_t
  Units: | msec
  Default value: | 0 (no periodic loss checks)
  When to Set: | Can only be set during object initialization.
  Version: | This option was implemented in LBM 4.2

## delivery_control_max_delay (hfx) <-

  The minimum interval that must expire before the HFX Receiver declares a message unrecoverable and delivers an unrecoverable loss message the application.

  By default, the HFX Receiver only checks loss when it receives new messages. To enable periodic loss checks, set the delivery_control_loss_check_interval (hfx) option.

  Scope: | hfx
  Type: | lbm_ulong_t
  Units: | msec
  Default value: | 10000 (10 seconds)
  When to Set: | Can only be set during object initialization.
  Version: | This option was implemented in LBM 4.2

## delivery_control_maximum_burst_loss (hfx) <-

  This controls the size of a topic sequence number gap past which the gap is declared a "burst loss".

  See Burst Loss for a detailed explanation of burst loss and its semantics. Note that the default value for HFX is different than for non-HFX receivers.

Attention
  For most use cases, Informatica recommends disabling "burst loss" by setting this option to a very large number, perhaps 1,000,000,000.

Note
  the burst loss control takes priority over all recovery methods. For example, if the receiver is reading a persistent stream and OTR is enabled, a gap longer than delivery_control_maximum_burst_loss will immediately declare the gap as unrecoverable without even trying to use OTR to recover. If message integrity is a high priority, delivery_control_maximum_burst_loss should be set to a very large value.

  See Hot Failover Across Multiple Contexts (HFX).

  Scope: | hfx
  Type: | lbm_uint_t
  Units: | number of messages (fragments)
  Default value: | 512
  When to Set: | Can only be set during object initialization.
  Version: | This option was implemented in LBM 4.2

## delivery_control_maximum_total_map_entries (hfx) <-

  The maximum number of map entries for the HFX order and loss maps.

  This is a soft limit. When the sum of the number of loss records and the number of messages held for ordering (messages that will be delivered once all prior messages have been delivered) is greater than this value, the oldest consecutive sequence of loss records will be declared lost immediately to reduce the number of outstanding map entries. A value of 0 indicates that the map should be allowed to grow without bound.

  Scope: | hfx
  Type: | size_t
  Units: | map entries
  Default value: | 200000
  When to Set: | Can only be set during object initialization.
  Version: | This option was implemented in LBM 4.2

## duplicate_delivery (hfx) <-

  Flag indicating whether duplicate messages should be discarded or simply marked as duplicates.

  Setting this to 1 overrides the hf_duplicate_delivery (receiver) setting on all underlying HFX Receivers.

  Scope: | hfx
  Type: | int
  When to Set: | Can only be set during object initialization.
  Version: | This option was implemented in LBM 4.2

  Value | Description
  --- | ---
  1 | The HFX delivers duplicate messages.
  0 | The HFX does not deliver duplicate messages. Default for all.

## hf_duplicate_delivery (receiver) <-

  Flag indicating if the Hot Failover receiver delivers duplicate messages or not.

  In normal operation, Hot Failover only delivers the first copy received of a message.

  See Hot Failover (HF) for more information.

  Scope: | receiver
  Type: | int
  When to Set: | Can only be set during object initialization.

  Value | Description
  --- | ---
  1 | The Hot Failover receiver delivers duplicate messages.
  0 | The Hot Failover receiver does not deliver duplicate messages. Default for all.

## hf_optional_messages (receiver) <-

  Indicates if a Hot Failover receiver can receive optional messages.

  See also Hot Failover (HF).

  Scope: | receiver
  Type: | int
  When to Set: | Can only be set during object initialization.
  Version: | This option was implemented in LBM 4.2.5/UME 3.2.5/UMQ 2.1.5

  Value | Description
  --- | ---
  1 | Hot Failover receivers can receive optional messages. Default for all.
  0 | Hot Failover receivers do not receive optional messages.

## hf_receiver (wildcard_receiver) <-

  Specifies whether to create hot failover receivers for each topic that maps to the wildcard receiver pattern.

  See Hot Failover (HF) for more information.

  Scope: | wildcard_receiver
  Type: | int
  When to Set: | Can only be set during object initialization.
  Version: | This option was implemented in UMS 5.2.2

  Value | Description
  --- | ---
  1 | Create hot failover receivers for each matched topic.
  0 | Normal wildcard receiver operation. Hot failover sequence numbers are ignored. Default for all.

## ordered_delivery (hfx) <-

  Flag indicating if the HFX Receiver orders messages before delivery.

  See Hot Failover Across Multiple Contexts (HFX).

  Scope: | hfx
  Type: | int
  When to Set: | Can only be set during object initialization.
  Version: | This option was implemented in LBM 4.2

  String value | Integer value | Description
  --- | --- | ---
  "1" | 1 | The HFX Receiver delivers messages in order. Default for all.
  "-1" | -1 | The HFX Receiver delivers messages as soon as they are received. In the case of fragmented messages, as soon as all fragments have been received and reassembled.